Processes and materials for casting and sintering green garnet thin films

ABSTRACT

Set forth herein are processes and materials for making ceramic thin films by casting ceramic source powders and precursor reactants, binders, and functional additives into unsintered thin films and subsequently sintering the thin films under controlled atmospheres and on specific substrates.

US NONPROVISIONAL PATENT APPLICATION

This application claims priority to, and the benefit of, U.S.Provisional Patent Application No. 62/195,172, entitled PROCESSES ANDMATERIALS FOR CASTING AND SINTERING GREEN GARNET THIN FILMS, which wasfiled Jul. 21, 2015, the contents of which are herein incorporated byreference in their entirety for all purposes.

FIELD

The present disclosure concerns precursors to inorganic thin films(e.g., green tapes or sintered films made from green tapes), processesfor using these precursors to make sintered thin films, and sinteredthin films made by the processes set forth herein. In some examples, thesintered thin films made by the processes set forth herein are useful assolid electrolytes in rechargeable batteries. In many examples, thegreen tapes which are set forth herein and used to make sintered thinfilms have a higher solid loading than known green tapes. The sinteredthin films prepared by the processes herein have a lower porosity, ahigher density, less defects, and, or, are prepared in higher yield thanknown sintered thin films.

BACKGROUND

Solid state ceramics, such as lithium-stuffed garnet materials andlithium borohydrides, oxides, sulfides, oxyhalides, and halides haveseveral advantages as materials for ion-conducting electrolyte membranesand separators in a variety of electrochemical devices including fuelcells and rechargeable batteries. When compared to their liquid-basedcounterparts, the aforementioned solid ceramics possess safety andeconomic advantages as well as advantages related to the material'ssolid state and density which allows for correspondingly high volumetricand gravimetric energy densities when these materials are incorporatedinto electrochemical devices as electrolyte separators. Solid state ionconducting ceramics are well suited for solid state electrochemicaldevices because of their high ion conductivity properties in the solidstate, their electric insulating properties, as well as their chemicalcompatibility with a variety of species such as lithium metal and theirstability to a wide window of voltages.

Although solid state ion conducting ceramics have a series ofadvantageous and beneficial properties, these materials suffer from arange of issues related to forming green films (i.e., green tapes) andto subsequently sintering these green films. When solid state ionconducting ceramics are typically formulated as thin films and sintered,these films have a tendency to stick to the substrate on which they areprepared, to crack or warp on account of the processing conditions, orare too brittle post-sintering to handle and manipulate. In particular,during sintering of thin films, these films have a tendency to crack,warp, or otherwise have surface deteriorations.

There is therefore a series of problems in the relevant field related tocasting green tapes of ceramics, such as but not limited to garnets andlithium sulfides, and to sintering these green tapes to prepare highdensity garnet thin films. What is needed in the relevant field is, forexample, new materials and processes for casting green tapes and forsintering the same. The instant disclosure sets forth such materials andprocesses, in addition to making and using the same, and other solutionsto problems in the relevant field.

SUMMARY

In one embodiment, the instant disclosure sets forth methods for castinga thin film tape, in which the methods include, generally, providing atleast one source power, modifying the at least one source powder toprepare a modified source powder, providing a slurry of the modifiedsource powder, casting the slurry to form a green tape, drying the greentape; and sintering the green tape to form a sintered thin film.

In a second embodiment, the instant disclosure sets forth a slurry forcasting a green tape, in which the slurry includes a source powder,optionally precursors to the source powder, and at least one memberselected from binders, dispersants, and solvents.

In a third embodiment, the instant disclosure sets forth a method forsintering a green tape, the method including: (a) providing at least onesource powder; (b) modifying the at least one source powder to prepare amodified source powder; (c) providing a slurry of the modified sourcepowder; (d) casting the slurry to form a green tape; (e) drying thegreen tape; and (f) sintering the green tape; thereby sintering a greentape.

In a fourth embodiment, the instant disclosure sets forth a slurry forpreparing a cast green film, the slurry including:

at least two or more of:

-   -   a solvent selected from the group consisting of methanol,        ethanol, MEK, isopropanol, acetone, cyclohexanone, toluene,        acetic acid, and benzene;    -   a binder selected from the group consisting of fish oil, PVB,        KD1, an acrylic acid, triton, phosphate esters, and derivatives        thereof;    -   a plasticizer selected from the group consisting of a benzyl        butyl phthalate or di-butyl phthalate;    -   a pH modifier;    -   a sintering aid selected from the group consisting; and    -   a source powder selected from a lithium-stuffed garnet

In a fifth embodiment, the instant disclosure sets forth a green tape,including:

-   -   a source powder;    -   a solvent;    -   a binder; and    -   a dispersant;    -   wherein the green tape has a picnometry density greater than 3.9        and less than 5.0.

In a sixth embodiment, the instant disclosure sets forth a method ofmaking a green tape, including the following steps: (a) providing aslurry; (b) providing a binder mixture; (c) mixing the slurry with thebinder mixture to form a mixed slurry; and (d) casting the mixed slurryto provide a green tape, wherein the green tape has a total organiccontent of about 10-25% w/w.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 shows an example flow chart in accordance with an embodiment ofthe methods set forth herein.

FIG. 2 shows a scanning electron microscopy (SEM) image of a green tapemade by the casting methods set forth in Example 1. The tape include 15%binder, the garnet had a d₅₀ of about 180 nm, and a density of 2.3g/cm³. The organic portion is labeled 201, and the inorganic portion islabeled 202.

FIG. 3 shows an optical image of a 100-200 μm sintered green tape,prepared by Example 3.

FIG. 4 shows a scanning electron microscopy (SEM) image of a sinteredtape made by Example 2 with slurry composition 1 and binder composition1.

The figures depict various embodiments of the present disclosure forpurposes of illustration only. One skilled in the art will readilyrecognize from the following discussion that alternative embodiments ofthe structures and methods illustrated herein may be employed withoutdeparting from the principles described herein.

The following description is presented to enable one of ordinary skillin the art to make and use the disclosed subject matter and toincorporate it in the context of particular applications. Variousmodifications, as well as a variety of uses in different applicationswill be readily apparent to those skilled in the art, and the generalprinciples defined herein may be applied to a wide range of embodiments.Thus, the present disclosure is not intended to be limited to theembodiments presented, but is to be accorded the widest scope consistentwith the principles and novel features disclosed herein.

In the following detailed description, numerous specific details are setforth in order to provide a more thorough understanding of the presentdisclosure. However, it will be apparent to one skilled in the art thatthe present disclosure may be practiced without necessarily beinglimited to these specific details. In other instances, well-knownstructures and devices are shown in block diagram form, rather than indetail, in order to avoid obscuring the present disclosure.

DETAILED DESCRIPTION

The disclose herein sets forth green tapes, processes for making thesetapes, and processes for sintering these tapes. The processes hereinproduce sintered thin films having improved surface qualities whencompared with films prepared by conventionally known methods. Some ofthe films prepared by the methods described herein are prepared withuniformly rough (i.e., smooth) surfaces. These films have a surface, assintered, which is suitable for incorporation into an electrochemicaldevice without further processing, such as polishing or lapping.Depending on the particular application, it may be necessary to processthe sintered films prepared herein by polishing or lapping, but forother applications the films, as sintered by the methods set forthherein, are suitable for electrochemical device applications. In someexamples, the films prepared herein have a surface roughness less than 5μm post-sintering.

A. DEFINITIONS

As used herein, “providing” refers to the provision of, generation or,presentation of, or delivery of that which is provided. Providingincludes making something available. For example, providing a powerrefers to the process of making the powder available, or delivering thepowder, such that the powder can be used as set forth in a methoddescribed herein. As used herein, providing also means measuring,weighing, transferring combining, or formulating.

As used herein, “casting” means to provide, deposit, or deliver a castsolution or slurry onto a substrate. Casting includes, but is notlimited to, slot casting, dip coating, and doctor blading. As usedherein, the phrase “slot casting,” refers to a deposition processwhereby a substrate is coated, or deposited, with a solution, liquid,slurry, or the like by flowing the solution, liquid, slurry, or thelike, through a slot or mold of fixed dimensions that is placed adjacentto, in contact with, or onto the substrate onto which the deposition orcoating occurs. In some examples, slot casting includes a slot openingof about 1 to 100 μm. As used herein, the phrase “dip casting” or “dipcoating” refers to a deposition process whereby substrate is coated, ordeposited, with a solution, liquid, slurry, or the like, by moving thesubstrate into and out of the solution, liquid, slurry, or the like,often in a vertical fashion. As used herein, “casting a slurry” refersto a process wherein a slurry is deposited onto, or adhered to, asubstrate. Casting can include, but is not limited to, slot casting anddip casting. As used herein, the phrase “slot casting,” refers to adeposition process whereby a substrate is coated, or deposited, with asolution, liquid, slurry, or the like by flowing the solution, liquid,slurry, or the like, through a slot or mold of fixed dimensions that isplaced adjacent to, in contact with, or onto the substrate onto whichthe deposition or coating occurs. In some examples, slot castingincludes a slot opening of about 1 to 100 μm. As used herein, the phrase“dip casting” or “dip coating” refers to a deposition process wherebysubstrate is coated, or deposited, with a solution, liquid, slurry, orthe like, by moving the substrate into and out of the solution, liquid,slurry, or the like, often in a vertical fashion. As used herein,casting also includes depositing, coating, or spreading a cast solutionor cast slurry onto a substrate. As used herein the phrase “casting afilm,” refers to the process of delivering or transferring a liquid or aslurry into a mold, or onto a substrate, such that the liquid or theslurry forms, or is formed into, a film. Casting may be done via doctorblade, meyer rod, comma coater, gravure coater, microgravure, reversecomma coater, slot dye, slip and/or tape casting, and other methodsknown to those skilled in the art.

As used herein the phrase “casting a film,” refers to the process ofdelivering or transferring a liquid or a slurry into a mold, or onto asubstrate, such that the liquid or the slurry forms, or is formed into,a film. Casting may be done via doctor blade, Meyer rod, comma coater,gravure coater, microgravure, reverse comma coater, slot dye, slipand/or tape casting, and other methods known to those skilled in theart.

As used herein, the phrase “slot casting,” refers to a depositionprocess whereby a substrate is coated, or deposited, with a solution,liquid, slurry, or the like by flowing the solution, liquid, slurry, orthe like, through a slot or mold of fixed dimensions that is placedadjacent to, in contact with, or onto the substrate onto which thedeposition or coating occurs. In some examples, slot casting includes aslot opening of about 1 to 100 μm.

As used herein, the phrase “dip casting” or “dip coating” refers to adeposition process whereby substrate is coated, or deposited, with asolution, liquid, slurry, or the like, by moving the substrate into andout of the solution, liquid, slurry, or the like, often in a verticalfashion.

As used herein, the term “laminating” refers to the process ofsequentially depositing a layer of one precursor specie, e.g., a lithiumprecursor specie, onto a deposition substrate and then subsequentlydepositing an additional layer onto an already deposited layer using asecond precursor specie, e.g., a transition metal precursor specie. Thislaminating process can be repeated to build up several layers ofdeposited vapor phases. As used herein, the term “laminating” alsorefers to the process whereby a layer comprising an electrode, e.g.,positive electrode or cathode active material comprising layer, iscontacted to a layer comprising another material, e.g., garnetelectrolyte. The laminating process may include a reaction or use of abinder which adheres or physically maintains the contact between thelayers which are laminated. Laminating also refers to the process ofbringing together unsintered, i.e. “green” ceramic films.

As used herein, the phrase “green tape” or “green film” refers to anunsintered film including at least one member selected from garnetmaterials, precursors to garnet materials, binder, solvent, carbon,dispersant, or combinations thereof

As used herein, the phrase “film thickness” refers to the distance, ormedian measured distance, between the top and bottom faces of a film. Asused herein, the top and bottom faces refer to the sides of the filmhaving the largest surface area.

As used herein, the phrases “garnet precursor chemicals,” “chemicalprecursor to a Garnet-type electrolyte,” or “garnet chemical precursors”refers to chemicals which react to form a lithium stuffed garnetmaterial described herein. These chemical precursors include, but arenot limited to, lithium hydroxide (e.g., LiOH), lithium oxide (e.g.,Li₂O), lithium carbonate (e.g., LiCO₃), zirconium oxide (e.g., ZrO₂),lanthanum oxide (e.g., La₂O₃), aluminum oxide (e.g., Al₂O₃), aluminum(e.g., Al), aluminum nitrate (e.g., AlNO₃), aluminum nitratenonahydrate, aluminum (oxy) hydroxide (gibbsite and boehmite), galliumoxide, niobium oxide (e.g., Nb₂O₅), and tantalum oxide (e.g., Ta₂O₅).

As used herein, the phrase “subscripts and molar coefficients in theempirical formulas are based on the quantities of raw materialsinitially batched to make the described examples” means the subscripts,(e.g., 7, 3, 2, 12 in Li₇La₃Zr₂O₁₂ and the coefficient 0.35 in0.35Al₂O₃) refer to the respective elemental ratios in the chemicalprecursors (e.g., LiOH, La₂O₃, ZrO₂, Al₂O₃) used to prepare a givenmaterial, (e.g., Li₇La₃Zr₂O₁₂.0.35Al₂O₃). As used here, the phrase“characterized by the formula,” refers to a molar ratio of constituentatoms either as batched during the process for making that characterizedmaterial or as empirically determined.

As used herein the term “solvent,” refers to a liquid that is suitablefor dissolving or solvating a component or material described herein.For example, a solvent includes a liquid, e.g., toluene, which issuitable for dissolving a component, e.g., the binder, used in thegarnet sintering process.

As used herein the phrase “removing a solvent,” refers to the processwhereby a solvent is extracted or separated from the components ormaterials set forth herein. Removing a solvent includes, but is notlimited to, evaporating a solvent. Removing a solvent includes, but isnot limited to, using a vacuum or a reduced pressure to drive off asolvent from a mixture, e.g., an unsintered thin film. In some examples,a thin film that includes a binder and a solvent is heated or alsooptionally placed in a vacuum or reduced atmosphere environment in orderto evaporate the solvent to leave the binder, which was solvated, in thethin film after the solvent is removed.

As used herein, “thin” means, when qualifying a film, membrane, or thelike, a dimension less than 200 μm, more preferably less than 100 μm andin some cases between 0.1 and 60 μm.

As used herein, “film tape” refers to a roll or continuous layer ofcasted tape, either dry or not dry, which is sintered or can besintered.

As used herein, a “binder” refers to a material that assists in theadhesion of another material. For example, as used herein, polyvinylbutyral is a binder because it is useful for adhering garnet materials.Other binders include polycarbonates. Other binders may includepolymethylmethacrylates. These examples of binders are not limiting asto the entire scope of binders contemplated here but merely serve asexamples. Binders useful in the present disclosure include, but are notlimited to, polypropylene (PP), atactic polypropylene (aPP), isotactivepolypropylene (iPP), ethylene propylene rubber (EPR), ethylene pentenecopolymer (EPC), polyisobutylene (PIB), styrene butadiene rubber (SBR),polyolefins, polyethylene-co-poly-1-octene (PE-co-PO),PE-co-poly(methylene cyclopentane) (PE-co-PMCP), polymethyl-methacrylate (and other acrylics), acrylic, polyvinylacetacetalresin, polyvinylbutylal resin, PVB, polyvinyl acetal resin, stereoblockpolypropylenes, polypropylene polymethylpentene copolymer, polyethyleneoxide (PEO), PEO block copolymers, silicone, and the like.

As used here, the phrase “lithium-stuffed garnet electrolyte,” refers tooxides that are characterized by a crystal structure related to a garnetcrystal structure. Lithium-stuffed garnets include compounds having theformula Li_(A)La_(B)M′_(c)M″_(D)Zr_(E)O_(F),Li_(A)La_(B)M′_(C)M″_(D)Ta_(E)O_(F), orLi_(A)La_(B)M′_(C)M″_(D)Nb_(E)O_(F), wherein 4<A<8.5, 1.5<B<4, 0≦C≦2,0≦D≦2; 0≦E≦2, 10<F<13, and M″ and M″ are each, independently in eachinstance selected from Al, Mo, W, Nb, Sb, Ca, Ba, Sr, Ce, Hf, Rb, or Ta,or Li_(a)La_(b)Zr_(C)Al_(d)Me″_(e)O_(f), wherein 5<a<7.7; 2<b<4;0≦c≦2.5; 0≦d≦2; 0≦e≦2, 10<f<13 and Me″ is a metal selected from Nb, Ta,V, W, Mo, Ga, or Sb and as described herein. Garnets, as used herein,also include those garnets described above that are doped with Al₂O₃.Garnets, as used herein, also include those garnets described above thatare doped so that Al³⁺ substitutes for Li⁺. As used herein,lithium-stuffed garnets, and garnets, generally, include, but are notlimited to, Li_(7.0)La₃(Zr_(t1)+Nb_(t2)+Ta_(t3))O₁₂+0.35Al₂O₃; wherein(t1+t2+t3=subscript 2) so that the La:(Zr/Nb/Ta) ratio is 3:2. Also,garnet used herein includes, but is not limited to,Li_(x)La₃Zr₂O₁₂+yAl₂O₃, wherein x ranges from 5.5 to 9; and y rangesfrom 0 to 1. In some examples x is 6-7 and y is 1.0. In some examples xis 7 and y is 0.35. In some examples x is 6-7 and y is 0.7. In someexamples x is 6-7 and y is 0.4. Also, garnets as used herein include,but are not limited to, Li_(x)La₃Zr₂O₁₂+yAl₂O₃. Non-limiting examplelithium-stuffed garnet electrolytes are found, for example, in US PatentApplication Publication No. 2015-0200420 A1, which published Jul. 16,2015.

As used herein, garnet does not include YAG-garnets (i.e., yttriumaluminum garnets, or, e.g., Y₃Al₅O₁₂). As used herein, garnet does notinclude silicate-based garnets such as pyrope, almandine, spessartine,grossular, hessonite, or cinnamon-stone, tsavorite, uvarovite andandradite and the solid solutions pyrope-almandine-spessarite anduvarovite-grossular-andradite. Garnets herein do not includenesosilicates having the general formula X₃Y₂(SiO₄)₃ wherein X is Ca,Mg, Fe, and, or, Mn; and Y is Al, Fe, and, or, Cr.

As used herein the phrase “garnet-type electrolyte,” refers to anelectrolyte that includes a lithium stuffed garnet material describedherein as the ionic conductor. The advantages of Li-stuffed, garnetsolid state electrolytes are many, including as a substitution forliquid, flammable electrolytes commonly used in lithium rechargeablebatteries.

As used herein, the phrase “d₅₀ diameter” refers to the median size, ina distribution of sizes, measured by microscopy techniques or otherparticle size analysis techniques, such as, but not limited to, scanningelectron microscopy or dynamic light scattering. D₅₀ includes thecharacteristic dimension at which 50% of the particles are smaller thanthe recited size.

As used herein, the phrase “d₉₀ diameter” refers to the median size, ina distribution of sizes, measured by microscopy techniques or otherparticle size analysis techniques, such as, but not limited to, scanningelectron microscopy or dynamic light scattering. D₉₀ includes thecharacteristic dimension at which 90% of the particles are smaller thanthe recited size.

As used herein, a “thickness” by which is film is characterized refersto the distance, or median measured distance, between the top and bottomfaces of a film. As used herein, the top and bottom faces refer to thesides of the film having the largest surface area.

As used herein, the phrase “subscripts and molar coefficients in theempirical formulas are based on the quantities of raw materialsinitially batched to make the described examples” means the subscripts,(e.g., 7, 3, 2, 12 in Li₇La₃Zr₂O₁₂ and the coefficient 0.35 in0.35Al₂O₃) refer to the respective elemental ratios in the chemicalprecursors (e.g., LiOH, La₂O₃, ZrO₂, Al₂O₃) used to prepare a givenmaterial, (e.g., Li₇La₃Zr₂O₁₂.0.35Al₂O₃).

As used herein the phrase “sintering the film,” refers to a processwhereby a thin film, as described herein, is densified (made denser, ormade with a reduced porosity) through the use of heat sintering or fieldassisted sintering. Sintering includes the process of forming a solidmass of material by heat and/or pressure without melting it to the pointof complete liquification.

As used herein, the term “plasticizer” refers to an additive thatimparts either flexibility or plasticity to the green tape. It may be asubstance or material used to increase the binder's flexibility,workability, or distensibility. Flexibility is the ability to bendwithout breaking. Plasticity is the ability to permanently deform.

As used herein, the phrase “stress relieving,” refers to a process whicheliminates residual stress in a casted green tape during drying andassociated shrinkage. One method of stress relieving includes heatingthe green tape at a temperature above the glass transition temperatureof the organic components in the green tape to allow structural andstress rearrangement in the casted green tape to eliminate residualstress. Another method of stress relieving includes heating a castedgreen tape to 70° C. and holding at that temperature for a minute toallow casted green tape to relieve stress.

As used herein, the phrase “pH modifier,” refers to an acid or a basethat can be added to a slurry to adjust the acidity or basicity of theslurry in order to achieve better dispersion stability of cast slurry.pH modifiers include, but are not limited to, citric acid and ammoniahydroxide, as well as other equivalent pH modifiers.

As used herein, the phrase “as batched,” refers to the respective molaramounts of components as initially mixed or provided at the beginning ofa synthesis. For example, the formula Li₇La₃Zr₂O₁₂, as batched, meansthat the ratio of Li to La to Zr to O in the reagents used to makeLi₇La₃Zr₂O₁₂ was 7 to 3 to 2 to 12.

As used herein, a picnometry density is measured using a MicromeriticsAccuPycII 1340 Calibrate instrument. Using this instrument, a controlledamount of a powder sample is placed in a cup and its mass measured. Theinstrument is used to measure volume and calculate density bymass/volume.

As used herein, the phrase “sintering aid,” refers to an additive thatis used to either form lower the melting point of a liquid phase or thatallows for faster sintering than otherwise would be possible without thesintering add. Sintering aids assist in the diffusion/kinetics of atomsbeing sintered. For example, LiAlO₂ may be used as an additive in aslurry having garnet since the LiAlO₂ can form a liquid with the garnetat between about 1050 and 1100° C., which provides for fasterdensification of garnet during sintering.

As used herein, a particle size distribution (hereinafter “PSD”) ismeasured by light scattering, for example, using on a Horiba LA-950 V2particle size analyzer in which the solvents used for the analysisinclude toluene, IPA, or acetonitrile and the analysis includes aone-minute sonication before measurement.

As used herein, the phrase “source powder” refers to an inorganicmaterial used in a slurry set forth herein. In some examples, the sourcepowder is a lithium-stuffed garnet. For example, the source powder mayinclude a powder of Li₇La₃Zr₂O₁₂.0.5Al₂O₃.

As used herein, the phrase “phosphate ester,” refers to, for example,phosphate esters known as Hypermer KD-23™, Hypermer KD24™, Phoschem PD™,Phoschem R-6™, Phospholan PS-131™, and Rhodoline 4188™.

As used herein, the term “DBP” refers to the chemical having the formulaC₁₆H₂₂O₄, Dibutyl phthalate, having a Molecular weight of 278.35 g/mol.

As used herein, the term “BBP,” refers to benzyl butyl phthalate,C₁₉H₂₀O₄, and having a Molecular weight of 312.37 g/mol.

As used herein, the term “PEG,” refers to polyethylene glycol. Unlessotherwise specified, the molecular weight of the PEG is from 400 to 6000g/mol.

B. GREEN TAPES

In some examples set forth herein, the green tapes casted by the methodsset forth herein contain refractory and, or, ceramic materials that areformulated as ceramic particles intimately mixed with a binder. Thepurpose of this binder is, in part, to assist the sintering of theceramic particles to result in a uniform and thin film, or layer, ofrefractory or ceramic post-sintering. During the sintering process, thebinder burns (e.g., calcination) out of the sintering thin film. In someexamples, this binder burns out of the sintering film at a temperatureless than 700° C., less than 450° C., less than 400° C., less than 350°C., less than 300° C., less than 250° C., or in some examples less than200° C., or in some examples less than 150° C., or in some examples lessthan 100° C. During the binder removal, the oxygen and water partialpressures may be controlled.

C. METHOD OF MAKING

The composites set forth herein can be made by a variety of methods. Insome methods a slurry containing a source powder is prepared, thisslurry is cast onto a substrate or a setter plate, and then this slurryis dried and sintered to prepare a dried and sintered solid ionconducting ceramic. In certain examples, the substrate may include, forexample, Mylar, silicone coated Mylar, surfaces coated with polymers,surface modified polymers, or surface assembled monolayers adhered,attached, or bonded to a surface.

In one example, the methods set forth herein are substantially as setforth in FIG. 1. In FIG. 1, Method 100 is described. In this method, thefirst step includes slip preparation 101. This entails combining asolvent, dispersant, and a source powder such as garnet into a reactioncontainer (e.g., a 50 ml Nalgene bottle). Milling media is also added.In step 102, the combined contents are milled for 1 hour to 3 days. Inthe third step 103, the binder, plasticizer, and or, homogenizers areadded to the reaction container to form a slurry. In the fourth step104, the slurry is rolled by rolling the reaction container to blend thebinder. In the fifth step 105, the slurry is de-aired by a de-airingprocess to remove gas. In the sixth step 106, the slurry is cast by adoctor blade cast method onto a substrate (e.g., silicone coated Mylar).In the seventh step 107, the cast film is dried. In this step 107, thedrying is accomplished in a controlled fashion to avoid cracking ordefect formation in the film. In one example, the slurry included 70 gof garnet powder that had a d₅₀ of approximately 3 μm, 16 g of MEKsolvent, 1.4 g of phosphate ester, 8.4 g of poly methyl methacrylatebinder in 50% by weight (w/w) MEK, 3.5 g of a plasticizer (e.g., S-160),and 1.6 g of cyclohexanone.

D. SLURRY

In some examples, the binders suitable for use with the slurriesdescribed herein include binders, used to facilitate the adhesionbetween the Li-stuffed garnet particles, include, but are not limitedto, polypropylene (PP), polyvinyl butyral (PVB), poly ethyl methacrylate(PEMA), polyvinyl pyrrolidone (PVP), atactic polypropylene (aPP),isotactive polypropylene ethylene propylene rubber (EPR), ethylenepentene copolymer (EPC), polyisobutylene (PIB), styrene butadiene rubber(SBR), polyolefins, polyethylene-copoly-1-octene (PE-co-PO);PE-co-poly(methylene cyclopentane) (PE-co-PMCP); stereo blockpolypropylenes, polypropylene polymethylpentene copolymer, polypropylene carbonate, methyl methacrylate (or PMMA), ethyl methacrylate(or PEMA), and silicone. Other binders include binder is selectedpolypropylene (PP), atactic polypropylene (aPP), isotactic polypropylene(iPP), ethylene propylene rubber (EPR), ethylene pentene copolymer(EPC), polyisobutylene (PIB), styrene butadiene (SBR), polyolefins,polyethylene-co-poly-1-octene (PE-co-PO), PE-co-poly(methylenecyclopentene) (PE-co-PMCP), stereoblock polypropylenes, polypropylenepolymethyl pentene, polyethylene oxide (PEO), PEO block copolymers,silicone, and combinations thereof.

Examples of dispersants, include, but are not limited to, phosphateesters, esters such as fish oil, surfactants, fluorosurfactants,polyvinylpyridine (PVP), polyvinyl butadiene (PVB), polyalkylene amine,acrylic polymers.

In some examples, the slurry may also include a surfactant. Anon-limiting list of suitable surfactants includes cetylpyridiniumchloride, cetylpyridium bromide, and sodium dodecylbenzenesulfonate.

In some examples, the slurry may also include a pH modifier. Example pHmodifiers include, but are not limited to, glacial acetic acid, NH₄OH,monoethanol amine, NaOH, Na₂CO₃, and KOH.

In some examples, the slurry may also include a plasticizer. Exampleplasticizers include, but are not limited to, dibutyl phthalate, dioctylphthalate, and benzyl butyl phthalate.

In some examples, the slurry includes Li garnet powders or precursorsthat strongly interact with solvents or organic binders and whichincrease slurry viscosity via re-flocculation. In some examples, there-flocculation is at a high level that does not result in high qualityslurries and casted tapes. In these particular examples, the process canbe controlled by the addition of an agent which changes the pH of theslurry so that it has a stable dispersion in the slurry. In theseparticular examples, the process can also controlled by the addition ofless reactive solvents and, or, binders. In these examples, the slurrieshave good dispersion, low viscosity and minimal organic content.

E. CASTING

Some tape casting methods are known in the relevant filed and includethose set forth in Mistler, R. E. and Twiname, E. R, Tape Casting:Theory and Practice, 1^(st) Edition Wiley-American Ceramic Society; 1edition (Dec. 1, 2000), the entire contents of which is hereinincorporated by reference in its entirety for all purposes. Othercasting methods and materials as set forth in U.S. Pat. No. 5,256,609,to Dolhert, L. E., and entitled CLEAN BURNING GREEN TAPE CAST SYSTEMUSING ATACTIC POLYPROPYLENE BINDER), the entire contents of which isherein incorporated by reference in its entirety for all purposes.

In some methods set forth herein, the methods include casting a tape ofceramic source powder onto a substrate (e.g., porous or nonporousalumina, zirconia, garnet, alumina-zirconia, lanthanumalumina-zirconia). In some examples, the tape is prepared on a substratesuch as a silicone coated substrate (e.g., silicone coated Mylar, orsilicone coated Mylar on alumina).

In some methods set forth herein, the sintering films release volatilecomponents. These components can often result in cracking or surfacedeterioration in the sintering film unless setter plates are used whichallow for these volatile components to evaporate or volatilize away fromthe sintering film. In some particular examples, it is advantageous touse a porous setter plate to assist with the evaporation of thesevolatile components.

F. TAPE DRYING AFTER CASTING

In some examples, the methods set forth herein include drying a castedtape (e.g., a green film). In some methods, drying includes controllingthe temperature of the casted tape by, for example, using a heated bedon which to place or deposit the casted film, infrared (IR) heating, orconvection heating of the casted tape. In some methods, drying mayinclude using environmental controls such as, but not limited to,stagnant and, or, flowing environment (e.g., atmospheric air, dry air,inert gas, nitrogen gas, argon gas) to manage or to control the amountof solvent in the drying ambient. In these methods, the drying is usedto control the rate of solvent removal and to ensure that the cast filmdries from the substrate to the surface as opposed to from the surfaceto the substrate.

In some examples, prior to drying the cast green tape, the cast greentape includes a solvent which is an azeotrope. In some examples, thisazeotrope is a solvent comprises cyclohexanone at 10-25 weight % of thegreen tape. In some examples, the weight percent of cyclohexanone in theazeotrope is 10 weight %. In some examples, the weight percent ofcyclohexanone in the azeotrope is 11 weight %. In some examples, theweight percent of cyclohexanone in the azeotrope is 12 weight %. In someexamples, the weight percent of cyclohexanone in the azeotrope is 13weight %. In some examples, the weight percent of cyclohexanone in theazeotrope is 14 weight %. In some examples, the weight percent ofcyclohexanone in the azeotrope is 15 weight %. In some examples, theweight percent of cyclohexanone in the azeotrope is 16 weight %. In someexamples, the weight percent of cyclohexanone in the azeotrope is 17weight %. In some examples, the weight percent of cyclohexanone in theazeotrope is 18 weight %. In some examples, the weight percent ofcyclohexanone in the azeotrope is 19 weight %. In some examples, theweight percent of cyclohexanone in the azeotrope is 20 weight %. In someexamples, the weight percent of cyclohexanone in the azeotrope is 21weight %. In some examples, the weight percent of cyclohexanone in theazeotrope is 22 weight %. In some examples, the weight percent ofcyclohexanone in the azeotrope is 23 weight %. In some examples, theweight percent of cyclohexanone in the azeotrope is 24 weight %. In someexamples, the weight percent of cyclohexanone in the azeotrope is 25weight %. In some examples, the solvent is a combination of MEK:IPA. Incertain examples, the ratio of MEK:IPA is 1:1. In certain examples, theratio of MEK:IPA is 2:1. In certain examples, the ratio of MEK:IPA is3:1. In certain examples, the ratio of MEK:IPA is 4:1. In certainexamples, the ratio of MEK:IPA is 5:1. In certain examples, the ratio ofMEK:IPA is 5:1. n certain examples, the ratio of MEK:IPA is 7:1. Incertain examples, the ratio of MEK:IPA is 8:1. In certain examples, theratio of MEK:IPA is 5:1. In certain examples, the ratio of MEK:IPA is5:2. In certain examples, the ratio of MEK:IPA is 6:2. In certainexamples, the ratio of MEK:IPA is 7:2. In certain examples, the ratio ofMEK:IPA is 8:2. In certain examples, the ratio of MEK:IPA is 9:2. Incertain examples, the ratio of MEK:IPA is 10:3. In certain examples, theratio of MEK:IPA is 11:3. In certain examples, the ratio of MEK:IPA is5:3. In certain examples, the ratio of MEK:IPA is 6:3. In certainexamples, the ratio of MEK:IPA is 7:3. In certain examples, the ratio ofMEK:IPA is 8:3. In certain examples, the ratio of MEK:IPA is 9:3. Incertain examples, the ratio of MEK:IPA is 10:3. In certain examples, theratio of MEK:IPA is 11:3.

In some examples, after the green tape is dried, the total amount ofmaterial other than the source powder is about 10-25% by weight of thegreen tape. In some examples the total amount of material other than thesource powder is 10% by weight of the green tape. In some examples thetotal amount of material other than the source powder is 11% by weightof the green tape. In some examples the total amount of material otherthan the source powder is 12% by weight of the green tape. In someexamples the total amount of material other than the source powder is13% by weight of the green tape. In some examples the total amount ofmaterial other than the source powder is 14% by weight of the greentape. In some examples the total amount of material other than thesource powder is 15% by weight of the green tape. In some examples thetotal amount of material other than the source powder is 16% by weightof the green tape. In some examples the total amount of material otherthan the source powder is 17% by weight of the green tape. In someexamples the total amount of material other than the source powder is18% by weight of the green tape. In some examples the total amount ofmaterial other than the source powder is 19% by weight of the greentape. In some examples the total amount of material other than thesource powder is 20% by weight of the green tape. In some examples thetotal amount of material other than the source powder is 21% by weightof the green tape. In some examples the total amount of material otherthan the source powder is 22% by weight of the green tape. In someexamples the total amount of material other than the source powder is23% by weight of the green tape. In some examples the total amount ofmaterial other than the source powder is 24% by weight of the greentape. In some examples the total amount of material other than thesource powder is 25% by weight of the green tape. In some of theseexamples, the amount of source powder is 60, 65, 70, 75, or 80% beweight for the green tape.

G. SETTER PLATES

In the methods described herein, the setter plates and the sinteringmethods set forth in International PCT Patent Applications Nos.PCT/US16/27886, filed on Apr. 15, 2016, and PCT/US16/27922, filed onApr. 15, 2016, the content of both patent applications is incorporatedherein by reference in its entirety for all purposes.

In some examples, the green films prepared by the methods herein, andthose incorporated by reference, are sintered between setter plates. Insome examples, these setter plates are composed of a metal, an oxide, anitride, a metal, oxide or nitride with an organic or silicone laminatelayer thereupon. In certain examples, the setter plates are selectedfrom the group consisting of platinum (Pt) setter plates, palladium (Pd)setter plates, gold (Au) setter plates, copper (Cu) setter plates,aluminum (Al) setter plates, alumina setter plates, porous aluminasetter plates, steel setter plates, zirconium (Zr) setter plates,zirconia setter plates, porous zirconia setter plates, lithium oxidesetter plates, porous lithium oxide setter plates, lanthanum oxidesetter plates, porous lanthanum oxide setter plates, garnet setterplates, porous garnet setter plates, lithium-stuffed garnet setterplates, porous lithium-stuffed garnet setter plates, and combinationsthereof. In some examples, the setter plates are garnet setter plates orporous garnet setter plates.

In some examples, the green films prepared by the methods herein, andthose incorporated by reference, are sintered on at least one setterplate. In some examples, these setter plates are composed of a metal, anoxide, a nitride, a metal, oxide or nitride with an organic or siliconelaminate layer thereupon. In certain examples, the setter plates areselected from the group consisting of platinum (Pt) setter plates,palladium (Pd) setter plates, gold (Au) setter plates, copper (Cu)setter plates, aluminum (Al) setter plates, alumina setter plates,porous alumina setter plates, steel setter plates, zirconium (Zr) setterplates, zirconia setter plates, porous zirconia setter plates, lithiumoxide setter plates, porous lithium oxide setter plates, lanthanum oxidesetter plates, Lithium zirconium oxide (Li₂ZrO₃) setter plates, Lithiumaluminum oxide (LiAlO₂) setter plates, porous lanthanum oxide setterplates, garnet setter plates, porous garnet setter plates,lithium-stuffed garnet setter plates, porous lithium-stuffed garnetsetter plates, and combinations of the aforementioned.

In some examples, the green films prepared by the methods herein, andthose incorporated by reference, are sintered between setter plates inwhich a metal powder is positioned between the setter plate and thegreen film. In some examples, these setter plates are composed of ametal, an oxide, a nitride, a metal, oxide or nitride with an organic orsilicone laminate layer thereupon. In certain examples, the setterplates are selected from the group consisting of platinum (Pt) setterplates, palladium (Pd) setter plates, gold (Au) setter plates, copper(Cu) setter plates, aluminum (Al) setter plates, alumina setter plates,porous alumina setter plates, steel setter plates, zirconium (Zr)setter, zirconia setter plates, porous zirconia setter plates, lithiumoxide setter plates, porous lithium oxide setter plates, lanthanum oxidesetter plates, Lithium zirconium oxide (Li₂ZrO₃) setter plates, Lithiumaluminum oxide (LiAlO₂) setter plates, porous lanthanum oxide setterplates, Lithium zirconium oxide (Li₂ZrO₃) setter plates, Lithiumaluminum oxide (LiAlO₂) setter plates, garnet setter plates, porousgarnet setter plates, lithium-stuffed garnet setter plates, and porouslithium-stuffed garnet setter plates, and combinations of theaforementioned. In these particular examples, the metal powder isselected from Ni power, Cu powder, Au powder, Fe powder, or combinationsthereof

In some examples, the green films prepared by the methods herein, andthose incorporated by reference, are sintered between setter plates inwhich a metal layer or film is positioned between the setter plate andthe green film. In some examples, these setter plates are composed of ametal, an oxide, a nitride, a metal, oxide or nitride with an organic orsilicone laminate layer thereupon. In certain examples, the setterplates are selected from the group consisting of platinum (Pt) setterplates, palladium (Pd) setter plates, gold (Au) setter plates, copper(Cu) setter plates, aluminum (Al) setter plates, alumina setter plates,porous alumina setter plates, steel setter plates, zirconium (Zr),zirconia setter plates, porous zirconia setter plates, lithium oxidesetter plates, porous lithium oxide setter plates, lanthanum oxidesetter plates, porous lanthanum oxide setter plates, garnet setterplates, porous garnet setter plates, lithium-stuffed garnet setterplates, porous lithium-stuffed garnet setter plates, magnesia setterplates, porous magnesia setter plates. In these particular examples, themetal powder is selected from Ni power, Cu powder, Mg powder, Mn power,Au powder, Fe powder, or combinations thereof.

During certain sintering conditions, a layer of particles (e.g., asetter sheet) or powder may be placed between the green film and thesetter plates to assist with the sintering of the green film. As thegreen film sinters, it tends to shrink and densify which if notcontrolled can lead to cracking or other mechanical defects in the film.In some of these examples, the layer of particles comprises a uniformlayer of particles. In some other of these examples, the layer ofparticles comprises a uniform layer of inert, or non-reactive with thegreen film, particles. In some sintering conditions, the layer ofparticles is provided as a sheet of particles. In some examples, thethickness of the sheet or layer or particles is about equal to the sizeof the particles in the sheet or layer. In other examples, the inertparticles positions between the green film and the setter plate(s) ispositioned between the contact surfaces of the green film and the partsof the green film which are being sintered. In some continuous sinteringprocesses, the setter plates and, or, the particles, layers, or sheetswhich are placed between the setter plates and the green film, may bemoved or repositioned during the sintering process so that a continuousroll of sintered film is prepared in a continuous process. In thesecontinuous processes, the setter plates and the particles, layers, orsheets, move in conjunction with the movement of the green film so thatthe portion of the green film being sintering is in contact with theparticles, layers, or sheets which are also in contact with the setterplates. In some instances, the layers or sheets are prepared with aparticular weight to prevent tape warping and surface deterioration.

In some of the examples described herein, the layer or sheet of inertand, or, uniform particles (or powders) assists the sintering process byproviding a minimal amount of friction between the film and the setterplates so that the film is not strained as it sinters and reduces involume and increases in density. By reducing the friction forces on thefilm, the green film can shrink with minimal stress during the sinteringprocess. This provides for improved sintered films that do not stick tothe setter plates, which do not distort during the sintering process,and which do not crack during the sintering process or thereafter.

In some examples described herein, other setter plates may be used, forexample in combination with the lithium stuffed garnet setter platesdescribed herein, so long as that other setter plate has a high meltingpoint, a high lithium activity, and a stability in reducing environment.Some examples of these other materials include a member selected fromLi₂ZrO₃, xLi₂O-(1−x)SiO₂ (where x=0.01-0.99), aLi₂O-bB₂O₃-cSiO₂ (wherea+b+c=1), LiLaO₂, LiAlO₂, Li₂O, Li₃PO4, a Li-stuffed garnet, orcombinations thereof. Additionally, these other setter plates should notinduce a chemical potential in the sintering film which results in Lidiffusion out of the sintering film and into the setter plate.Additional materials include lanthanum aluminum oxide, pyrochlore andmaterials having a lithium concentration of greater than 0.01 mol/cm³.In some examples, the setter material may be provided as a powder or ina non-planar shape.

H. SOLVENTS

In some examples, the slurry includes a solvent selected fromisopropanol, water, butanol, tetrahydrofuran (THF), optionally with abinder (e.g., PVB), and optionally with a plasticizer. In some examples,the solvent includes about 10-30% w/w isopropanol, 1-10% w/w water,1-10% w/w butanol, and 10-30% w/w tetrahydrofuran (THF) [e.g. 100 gramsgarnet, 12 grams binder, 12 grams DBP, 20-30 grams solvent]. In someexamples, the solvent includes about 20-30% w/w isopropanol, 3-6% w/wwater, 3-6% w/w butanol, and 20-30% w/w tetrahydrofuran (THF). In someexamples, the binder is 5% w/w. In some examples, the plasticizer is 5%w/w. In these examples, the garnet or calcined precursor materialsrepresents the remaining % w/w (e.g., 40, 50, 60%, 70%, or 75% w/w). Insome examples, a dispersant is used during the milling process. In someexamples, the dispersant is a phosphate ester. In some examples, theplasticizer is dibutyl thalate or benzyl butyl phthalate. In someexamples, the solvent is butanol and THF. In some examples, the solventis butanol, water and THF. In some examples, the solvent is butanol,water, toluene, and THF. In some examples, the solvent is butanol andtoluene. In some examples, the solvent is butanol, water and THF.

Examples of solvents include toluene, ethanol, diacetone alcohol, andcombinations thereof. Other examples of solvents include combinations ofisopropanol (IPA, anhydrous), butanol, and toluene. Other examples ofsolvents include methanol, ethanol, isopropanol, butanol, pentanol,hexanol, toluene, xylene, xylenes:butyl alcohol, cyclohexanone,tetrahydrofuran, toluene:ethanol, acetone, N-methyl-2-pyrrolidone (NMP)diacetone alcohol, ethyl acetate, acetonitrile, hexane, nonane,dodecane, methyl ethyl ketone (MEK), and combinations thereof.

In some examples, the solvent is a combination of MEK:IPA. In certainexamples, the ratio of MEK:IPA is 1:1. In certain examples, the ratio ofMEK:IPA is 2:1. In certain examples, the ratio of MEK:IPA is 3:1. Incertain examples, the ratio of MEK:IPA is 4:1. In certain examples, theratio of MEK:IPA is 5:1. In certain examples, the ratio of MEK:IPA is5:1. n certain examples, the ratio of MEK:IPA is 7:1. In certainexamples, the ratio of MEK:IPA is 8:1. In certain examples, the ratio ofMEK:IPA is 5:1. In certain examples, the ratio of MEK:IPA is 5:2. Incertain examples, the ratio of MEK:IPA is 6:2. In certain examples, theratio of MEK:IPA is 7:2. In certain examples, the ratio of MEK:IPA is8:2. In certain examples, the ratio of MEK:IPA is 9:2. In certainexamples, the ratio of MEK:IPA is 10:3. In certain examples, the ratioof MEK:IPA is 11:3. In certain examples, the ratio of MEK:IPA is 5:3. Incertain examples, the ratio of MEK:IPA is 6:3. In certain examples, theratio of MEK:IPA is 7:3. In certain examples, the ratio of MEK:IPA is8:3. In certain examples, the ratio of MEK:IPA is 9:3. In certainexamples, the ratio of MEK:IPA is 10:3. In certain examples, the ratioof MEK:IPA is 11:3.

In of the above examples, the solvent further comprises cyclohexanone at10-25 weight %. In some examples, the weight percent of cyclohexanone inthe slurry is 10 weight %. In some examples, the weight percent ofcyclohexanone in the slurry is 11 weight %. In some examples, the weightpercent of cyclohexanone in the slurry is 12 weight %. In some examples,the weight percent of cyclohexanone in the slurry is 13 weight %. Insome examples, the weight percent of cyclohexanone in the slurry is 14weight %. In some examples, the weight percent of cyclohexanone in theslurry is 15 weight %. In some examples, the weight percent ofcyclohexanone in the slurry is 16 weight %. In some examples, the weightpercent of cyclohexanone in the slurry is 17 weight %. In some examples,the weight percent of cyclohexanone in the slurry is 18 weight %. Insome examples, the weight percent of cyclohexanone in the slurry is 19weight %. In some examples, the weight percent of cyclohexanone in theslurry is 20 weight %. In some examples, the weight percent ofcyclohexanone in the slurry is 21 weight %. In some examples, the weightpercent of cyclohexanone in the slurry is 22 weight %. In some examples,the weight percent of cyclohexanone in the slurry is 23 weight %. Insome examples, the weight percent of cyclohexanone in the slurry is 24weight %. In some examples, the weight percent of cyclohexanone in theslurry is 25 weight %. In some examples, the solvent is a combination ofMEK:IPA. In certain examples, the ratio of MEK:IPA is 1:1. In certainexamples, the ratio of MEK:IPA is 2:1. In certain examples, the ratio ofMEK:IPA is 3:1. In certain examples, the ratio of MEK:IPA is 4:1. Incertain examples, the ratio of MEK:IPA is 5:1. In certain examples, theratio of MEK:IPA is 5:1. n certain examples, the ratio of MEK:IPA is7:1. In certain examples, the ratio of MEK:IPA is 8:1. In certainexamples, the ratio of MEK:IPA is 5:1. In certain examples, the ratio ofMEK:IPA is 5:2. In certain examples, the ratio of MEK:IPA is 6:2. Incertain examples, the ratio of MEK:IPA is 7:2. In certain examples, theratio of MEK:IPA is 8:2. In certain examples, the ratio of MEK:IPA is9:2. In certain examples, the ratio of MEK:IPA is 10:3. In certainexamples, the ratio of MEK:IPA is 11:3. In certain examples, the ratioof MEK:IPA is 5:3. In certain examples, the ratio of MEK:IPA is 6:3. Incertain examples, the ratio of MEK:IPA is 7:3. In certain examples, theratio of MEK:IPA is 8:3. In certain examples, the ratio of MEK:IPA is9:3. In certain examples, the ratio of MEK:IPA is 10:3. In certainexamples, the ratio of MEK:IPA is 11:3.

In some examples, the solvent in the slurry includes MEK:IPA andcyclohexanone. In certain examples, the weight percent of cyclohexanonein the slurry is 10 weight %. In some examples, the weight percent ofcyclohexanone in the slurry is 11 weight %. In some examples, the weightpercent of cyclohexanone in the slurry is 12 weight %. In some examples,the weight percent of cyclohexanone in the slurry is 13 weight %. Insome examples, the weight percent of cyclohexanone in the slurry is 14weight %. In some examples, the weight percent of cyclohexanone in theslurry is 15 weight %. In some examples, the weight percent ofcyclohexanone in the slurry is 16 weight %. In some examples, the weightpercent of cyclohexanone in the slurry is 17 weight %. In some examples,the weight percent of cyclohexanone in the slurry is 18 weight %. Insome examples, the weight percent of cyclohexanone in the slurry is 19weight %. In some examples, the weight percent of cyclohexanone in theslurry is 20 weight %. In some examples, the weight percent ofcyclohexanone in the slurry is 21 weight %. In some examples, the weightpercent of cyclohexanone in the slurry is 22 weight %. In some examples,the weight percent of cyclohexanone in the slurry is 23 weight %. Insome examples, the weight percent of cyclohexanone in the slurry is 24weight %. In some examples, the weight percent of cyclohexanone in theslurry is 25 weight %. In some examples, the solvent is a combination ofMEK:IPA. In certain examples, the ratio of MEK:IPA is 1:1. In certainexamples, the ratio of MEK:IPA is 2:1. In certain examples, the ratio ofMEK:IPA is 3:1. In certain examples, the ratio of MEK:IPA is 4:1. Incertain examples, the ratio of MEK:IPA is 5:1. In certain examples, theratio of MEK:IPA is 5:1. n certain examples, the ratio of MEK:IPA is7:1. In certain examples, the ratio of MEK:IPA is 8:1. In certainexamples, the ratio of MEK:IPA is 5:1. In certain examples, the ratio ofMEK:IPA is 5:2. In certain examples, the ratio of MEK:IPA is 6:2. Incertain examples, the ratio of MEK:IPA is 7:2. In certain examples, theratio of MEK:IPA is 8:2. In certain examples, the ratio of MEK:IPA is9:2. In certain examples, the ratio of MEK:IPA is 10:3. In certainexamples, the ratio of MEK:IPA is 11:3. In certain examples, the ratioof MEK:IPA is 5:3. In certain examples, the ratio of MEK:IPA is 6:3. Incertain examples, the ratio of MEK:IPA is 7:3. In certain examples, theratio of MEK:IPA is 8:3. In certain examples, the ratio of MEK:IPA is9:3. In certain examples, the ratio of MEK:IPA is 10:3. In certainexamples, the ratio of MEK:IPA is 11:3.

In certain examples, the ratio of MEK:IPA is 7:3

In some examples, the solvent is a combination of MEK, IPA, andcyclohexanone.

In some examples, the solvent herein further includes water.

I. SINTERING

The green films set forth herein can be sintered by sintering methodsknown in the relevant field. The sintering conditions set forth inPCT/US2014/059578, Garnet Materials for Li Secondary Batteries andMethods of Making and Using Garnet Materials, filed Oct. 7, 2014, areherein incorporated by reference in their entirety for all purposes.

The green films set forth herein can be sintered in ovens open to theatmosphere. In some examples, the films are sintered in an O₂ richatmosphere. In other examples, the films are sintered in an Argon richatmosphere. In yet other examples, the films are sintered in an Argon/H₂atmosphere. In other examples, the films are sintered in an Argon/H₂Oatmosphere. In some examples, the atmosphere used to sinter the films isnot the same as the atmosphere used to cool the films after they havebeen sintered.

In some examples, the method includes sintering the film, whereinsintering comprises heat sintering. In some of these examples, heatsintering includes heating the film in the range from about 700° C. toabout 1200° C. for about 1 to about 600 minutes and in atmosphere havingan oxygen partial pressure in the range of 1 e-1 atm to 1 e-15 atm.

In any of the methods set forth herein, heat sintering may includeheating the film in the range from about 700° C. to about 1250° C.; orabout 800° C. to about 1200° C.; or about 900° C. to about 1200° C.; orabout 1000° C. to about 1200° C.; or about 1100° C. to about 1200° C. Inany of the methods set forth herein, heat sintering can include heatingthe film in the range from about 700° C. to about 1100° C.; or about700° C. to about 1000° C.; or about 700° C. to about 900° C.; or about700° C. to about 800° C. In any of the methods set forth herein, heatsintering can include heating the film to about 700° C., about 750° C.,about 850° C., about 800° C., about 900° C., about 950° C., about 1000°C., about 1050° C., about 1100° C., about 1150° C., or about 1200° C. Inany of the methods set forth herein, heat sintering can include heatingthe film to 700° C., 750° C., 850° C., 800° C., 900° C., 950° C., 1000°C., 1050° C., 1100° C., 1150° C., or 1200° C. In any of the methods setforth herein, heat sintering can include heating the film to 700° C. Inany of the methods set forth herein, heat sintering can include heatingthe film to 750° C. In any of the methods set forth herein, heatsintering can include heating the film to 850° C. In any of the methodsset forth herein, heat sintering can include heating the film to 900° C.In any of the methods set forth herein, heat sintering can includeheating the film to 950° C. In any of the methods set forth herein, heatsintering can include heating the film to 1000° C. In any of the methodsset forth herein, heat sintering can include heating the film to 1050°C. In any of the methods set forth herein, heat sintering can includeheating the film to 1100° C. In any of the methods set forth herein,heat sintering can include heating the film to 1125° C. In any of themethods set forth herein, heat sintering can include heating the film to1150° C. In any of the methods set forth herein, heat sintering caninclude heating the film to 1200° C.

In any of the methods set forth herein, the methods may include heatingthe film for about 1 to about 600 minutes. In any of the methods setforth herein, the methods may include heating the film for about 20 toabout 600 minutes. In any of the methods set forth herein, the methodsmay include heating the film for about 30 to about 600 minutes. In anyof the methods set forth herein, the methods may include heating thefilm for about 40 to about 600 minutes. In any of the methods set forthherein, the methods may include heating the film for about 50 to about600 minutes. In any of the methods set forth herein, the methods mayinclude heating the film for about 60 to about 600 minutes. In any ofthe methods set forth herein, the methods may include heating the filmfor about 70 to about 600 minutes. In any of the methods set forthherein, the methods may include heating the film for about 80 to about600 minutes. In any of the methods set forth herein, the methods mayinclude heating the film for about 90 to about 600 minutes. In any ofthe methods set forth herein, the methods may include heating the filmfor about 100 to about 600 minutes. In any of the methods set forthherein, the methods may include heating the film for about 120 to about600 minutes. In any of the methods set forth herein, the methods mayinclude heating the film for about 140 to about 600 minutes. In any ofthe methods set forth herein, the methods may include heating the filmfor about 160 to about 600 minutes. In any of the methods set forthherein, the methods may include heating the film for about 180 to about600 minutes. In any of the methods set forth herein, the methods mayinclude heating the film for about 200 to about 600 minutes. In any ofthe methods set forth herein, the methods may include heating the filmfor about 300 to about 600 minutes. In any of the methods set forthherein, the methods may include heating the film for about 350 to about600 minutes. In any of the methods set forth herein, the methods mayinclude heating the film for about 400 to about 600 minutes. In any ofthe methods set forth herein, the methods may include heating the filmfor about 450 to about 600 minutes. In any of the methods set forthherein, the methods may include heating the film for about 500 to about600 minutes. In any of the methods set forth herein, the methods mayinclude heating the film for about 1 to about 500 minutes. In any of themethods set forth herein, the methods may include heating the film forabout 1 to about 400 minutes. In any of the methods set forth herein,the methods may include heating the film for about 1 to about 300minutes. In any of the methods set forth herein, the methods may includeheating the film for about 1 to about 200 minutes. In any of the methodsset forth herein, the methods may include heating the film for about 1to about 100 minutes. In any of the methods set forth herein, themethods may include heating the film for about 1 to about 50 minutes.

In some examples, the sintering process may further include a filtrationstep.

In some examples, the sintering process may further include ade-aeration step.

In some examples, the sintering process may include sintering within aclosed, but not sealed, furnace (i.e., oven, heating chamber). In someof these examples, the sintering film is placed between setter plates,optionally with setter sheets or layers therebetween as well, and thesintering film is placed next to, or in close proximity to, asacrificial source of Li. This sacrificial source of Li helps to preventLi loss by way of evaporation from the sintering garnet. In someexamples, the closed system includes Argon gas, a mixture of Argon gasand either Hydrogen gas or water, Air, purified Air, or Nitrogen. Insome of these examples, the sacrificial source of Li has a highersurface area than the surface area of the green tape which is sintered.In some examples, the Li source and the sintering green film have thesame type of lithium-stuffed garnets.

J. SINTERING WITH OTHER DEVICE COMPONENTS

In certain examples, the green films are sintered while in contact withother components with which the post-sintered films would be combined ifused in an electrochemical device. For example, in some examples, thegreen films are layered or laminated to a positive electrode compositionso that after sintering the green film, the sintered film is adhered tothe positive electrode. In another example, the green film is sinteredwhile in contact with a metallic powder (e.g., nickel (Ni) powder). Asthe green film sinters, and the metal powder because a solid metal foil,the sintering film bonds to the metal foil. The advantage of thesesintering conditions is that more than one component of anelectrochemical device can be prepared in one step, thus savingmanufacturing time and resources.

K. MILLING

As described herein, several recited methods include methods stepsrelated to mixing and, or, method steps related to milling. Millingincludes ball milling. Milling also includes milling methods that useinert solvents such as, but not limited to, ethanol, isopropanol,toluene, ethyl acetate, methyl acetate, acetone, acetonitrile, orcombinations thereof. Depending on the material milled, the solvents maynot be inert. In some of these examples, milling includes milling withsolvents such as, but not limited to, ethanol, isopropanol, toluene,ethyl acetate, methyl acetate, acetone, acetonitrile, MEK, orcombinations thereof.

In some examples, the milling is ball milling. In some examples, themilling is horizontal milling. In some examples, the milling is attritormilling. In some examples, the milling is immersion milling. In someexamples, the milling is jet milling. In some examples, the milling issteam jet milling. In some examples, the milling is high energy milling.In some examples, the high energy milling process results in a milledparticle size distribution with d₅₀ of approximately 100 nm. In someexamples, the milling is immersion milling.

In some examples, high energy milling process is used to achieve aparticle size distribution with d50 of about 100 nm. In some examples,the solvent is toluene. In some examples, the solvent is isopropylalcohol (IPA). In some examples, the solvent is ethanol. In someexamples, the solvent is diacetone alcohol. In some examples, thesolvent is a polar solvents suitable for achieving the recited d50 size.

In some examples, the milling includes high energy wet milling processwith 0.3 mm yttria stabilized zirconium oxide grinding media beads. Insome examples, ball milling, horizontal milling, attritor milling, orimmersion milling can be used. In some examples, using a high energymilling process produces a particle size distribution of about d50-100nm to 5000 nm.

In some examples, the milling may include a classifying step such assieving, centrifugation, or other known laboratory of separatingparticles of different size and/or mass.

L. EXAMPLES

SEM Electron microscopy was performed in a Helios 600i or FEI Quanta.Surface Roughness was measured by an optical microscope such as theKeyence VR that may measure height and calculate a roughness value.

Sintering instruments used included 3″ laboratory tube furnace withcontrolled atmosphere in the partial pressure oxygen range of 1 e-1 to 1e-20 atm with a custom temperature and gas flow control system

Example 1 Method for Making and Sintering a Green Tape

A first slurry was prepared which included 18.75 g of a lithium-stuffedgarnet (as batched, Li_(7.1)Zr₂La₃O₁₂+0.5Al₂O₃) source powder mixed with12.25 g of isopropanol, 1.875 g of polyvinylbutyral, 1.875 g of dibutylphthalate, 2.81 g of phosphate ester, and 9 g of tetrahydrofuran.

A second slurry was prepared which included 18.75 g of a lithium-stuffedgarnet source powder, mixed with 12.25 g of isopropanol, 1.875 g ofpolyvinylbutyral, 1.875 g of dibutyl phthalate, 2.81 g of phosphateester, and 9 g of toluene.

A third slurry was prepared which included 18.75 g of a lithium-stuffedgarnet source powder mixed with 12.25 g of a mixed solvent whichincluded isopropanol and 20% by weight butanol, and 1.875 g ofpolyvinylbutyral, 1.875 g of dibutyl phthalate, and 2.81 g of phosphateester, and 9 g of tetrahydrofuran.

A fourth slurry was prepared which included 18.75 g of a lithium-stuffedgarnet source powder mixed with 12.25 g of a mixed solvent whichincluded isopropanol and 20% by weight butanol, 1.875 g ofpolyvinylbutyral, 1.875 g of dibutyl phthalate, 2.81 g of phosphateester, and 9 g of toluene.

The particle morphology of the lithium-stuffed garnet source powder,before and after attrition milling, for each slurry is illustrated inFIGS. 5 and 6, respectively.

In this example, a green tape was prepared by casting a slurry oflithium-stuffed garnet onto a substrate by doctor blading, subsequentlysintering the cast slurry by placing it between two porous garnet setterplates, and then removed from the setter plates. In one example, thetape cast from the slurry was sintered at 1100° C. for 1-5 hours. Inanother example, the tape was sintered at 1125° C. for 1-5 hours. Inanother example, the tape was sintered at 1150° C. for 1-5 hours. Priorto the sintering, the binder was burned out in high pressure O₂ (PO₂)and H₂O. During sintering the atmosphere around the sintering film had aPO₂ in the range 0.5-10⁻²⁰ atm.

Green tape made in this example using slurry composition 1 was analyzedby SEM microscopy as set forth in FIG. 2.

Example 2 Method for Making and Sintering a Green Tape

In this example, the following slurries (Slurry 1, Slurry 2 and Slurry3) were prepared having the following components at the recites weightpercent (%). The source powder was Li_(7.1)Zr₂La₃O₁₂+0.5Al₂O₃, asbatched. “Solids” below refers to the solid content of the Rhodoline4160.

density Slurry 1 components Slurry 2 components Milled slurry (g/cm3) byweight % by weight % IPA 0.7825 12.20% 10.72% Butanol 0.81   3.05% 2.68% THF 0.889  14.63% 12.87% Rhodoline 4160 1.03   9.15%  6.70% water1     6.86%  5.03% solids 1.132   2.29%  1.68% Garnet Powder 5.1  60.98% 67.02%

density Slurry 3 components Milled slurry (g/cm3) by weight % Garnet4.75  66.40% MEK 0.805 13.48% Ethanol 0.789 13.48% Rhodline 4160 1.1  6.64%

In this example, the following binder mixtures were prepared having thefollowing components at the recites weight percent (%):

density Binder mixture 1 Binder mixture 2 Binder mixture (g/cm3) byweight % by weight % Dibutyl 1.05  14.49% 14.49% phthalate Butvar B 79PVB 1.08  14.49% 14.49% IPA 0.7825 28.99% 18.55% Butanol 0.81   7.25% 4.64% THF 0.889  34.78% 22.26%

density Binder mixture 3 (g/cm3) by weight % MEK 0.805  31.55% Ethanol0.7781 31.55% B76 1.083  22.29% SANTICIZER 160 1.12  14.62%

Slurry 1 was combined with binder mixture 1 in a 2.4 weight ratio toform a mixed slurry. Slurry 2 was combined with binder mixture 2 in a2.1 weight ratio to form a mixed slurry. Slurry 3 was combined withbinder mixture 3 in a 2. weight ratio to form a mixed slurry.

In this example, a green tape was prepared by casting each mixed slurryonto a substrate by doctor blading, subsequently sintering the castslurry by placing it between two porous garnet setter plates, and thenremoved from the setter plates. In one example, the tape cast from theslurry was sintered at 1100° C. for 1-5 hours. In another example, thetape was sintered at 1125° C. for 1-5 hours. In another example, thetape was sintered at 1150° C. for 1-5 hours. Prior to the sintering, thebinder was burned out in high pressure O₂(PO₂) and H₂O. During sinteringthe atmosphere around the sintering film had a PO₂ in the range0.5-10⁻²⁰ atm.

Sintered films made in this example using slurry composition 1 andbinder mixture 1 were analyzed by SEM microscopy as set forth in FIG. 4.

Example 3 Method for Layering and Sintering a Green Tape

In this example, the slurries and binder mixtures were prepared andcombined as in Example 2. Next, a green tape was prepared by castingeach mixed slurry onto a substrate by doctor blading. The cast mixedslurry was allowed to dry in air to form a green tape. Next, a secondlayer of a green tape was deposited onto the dried green tape. Thisprocess was repeated until there were five layers of green tape stackedon top of each other. Then the stacked green tapes were sintered byplacing them between two porous garnet setter plates, and then removedfrom the setter plates. The stacked green tapes were sintered, in oneexample, at 1100° C. for 1-5 hours. In another example, the tape wassintered at 1125° C. for 1-5 hours. In another example, the tape wassintered at 1150° C. for 1-5 hours. Prior to the sintering, the binderwas burned out in high pressure O₂ (PO₂) and H₂O. During sintering theatmosphere around the sintering film had a PO₂ in the range

0.5-10⁻²⁰ atm.

Sintered films made using the aforementioned green tapes in this examplewere analyzed by optical imaging as set forth in FIG. 3.

The foregoing description of the embodiments of the disclosure has beenpresented for the purpose of illustration; it is not intended to beexhaustive or to limit the claims to the precise forms disclosed.Persons skilled in the relevant art can appreciate that using no morethan routine experimentation, numerous equivalents, modifications andvariations are possible in light of the above disclosure.

1. A method for sintering a green tape, the method comprising: (a)providing at least one source powder; wherein the at least one sourcepowder is a lithium-stuffed garnet powder; (b) modifying the at leastone source powder to prepare a modified source powder; (c) providing aslurry of the modified source powder; (d) casting the slurry to form agreen tape; (e) drying the green tape; and (f) sintering the green tape.2. The method of claim 1, wherein the amount of source powder in thegreen tape is at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90% byweight.
 3. (canceled)
 4. The method of claim 1, wherein the at least onesource powder is selected from the group consisting of lithium-stuffedgarnet, chemical precursors to lithium-stuffed garnet, and lithiumstuffed garnet with aluminum oxide dopants.
 5. The method of claim 1,wherein the at least one source powder is a powder of a lithium-stuffedgarnet.
 6. The method of claim 1, wherein the at least one source powderis Li_(x)Zr₂La₃O₁₂yAl₂O₃; wherein x ranges from 5 to 9; and y rangesfrom 0 to 1
 7. The method of claim 1, wherein the at least one sourcepowder is lithium-stuffed garnet.
 8. The method of claim 1, wherein themodifying the at least one source powder comprises modifying theparticle size distribution of the at least one source powder.
 9. Themethod of claim 8, wherein the particle size distribution has a d₅₀ ofabout 100 nm, 200 nm, 300 nm, 400 nm, 1 μm, 2 μm, 3 μm, or 4 μm. 10.-22.(canceled)
 23. The method of claim 1, wherein the surface area of the atleast one source powder is increased to at least 5 m²/g during themodifying the at least one source powder.
 24. The method of claim 22,wherein the surface area of the at least one source powder is increasedto at least 8 m²/g and less than 15 m²/g during the modifying the atleast one source powder.
 25. The method of claim 1, wherein themodifying the at least one source powder comprises decreasing an averageparticle size of particles of the at least one source powder. 26.-31.(canceled)
 32. The method of claim 1, further comprising stressrelieving the green tape prior to the sintering.
 33. The method of claim1, further comprising laminating more than one green tape together. 34.The method of claim 1, further comprising laminating one green tape onto a second green tape. 35.-36. (canceled)
 37. The method of claim 1,wherein the at least one source powder is a Li-stuffed garnet compoundcharacterized by the formula Li_(x)La_(y)Zr_(z)O_(t).qAl₂O₃, wherein4<x<10, 1<y<4, 1<z<3, 6<t<14, and 0≦q≦1.
 38. The method of claim 1,wherein the at least one source powder is a Li-stuffed garnet compoundcharacterized by the formula Li_(7-x)La₃Zr₂O₁₂.qAl₂O₃, wherein q is 0,0.3, 0.35, 0.5, 0.75, or 1.0 and 0≦x≦1.
 39. (canceled)
 40. The method ofclaim 1, wherein providing the slurry comprises formulating the slurryby mixing at least two or more of: a solvent selected from the groupconsisting of methanol, MEK, ethanol, propanol, isopropanol (IPA),acetone, cyclohexanol, toluene, acetic acid, benzene, and a combinationthereof; a binder selected from the group consisting of fish oil, PVB,KD1, an acrylic acid, triton, phosphate esters, derivatives thereof, andcombinations thereof; a plasticizer selected from the group consistingof a benzyl butyl phthalate and di-butyl phthalate; a pH modifier; asintering aid; and a source powder selected from a lithium-stuffedgarnet.
 41. (canceled)
 42. The method of claim 1, wherein the modifyingcomprises classifying the at least one source powder based on a particlesize. 43.-44. (canceled)
 45. The method of claim 1, wherein the slurryhas a solid loading of 1% to 99 wt %, wherein the solid loading refersto the amount of source powder.
 46. The method of claim 1, wherein theslurry, when dried, has about 80% w/w source powder.
 47. The method ofclaim 1, wherein the slurry, when dried, has about 10-25% w/w organiccontent, wherein the organic content refers to slurry components otherthan the source powder.
 48. The method of claim 1, wherein the slurry,when dried, has about 10-25% w/w organic content, wherein the organiccontent refers to slurry components other than the source powder whereinthe source powder is a lithium-stuffed garnet.
 49. The method of claim1, wherein the amount of binder and plasticizer in the slurry is about10-25% w/w organic content, wherein the organic content refers to slurrycomponents other than the source powder wherein the source powder is alithium-stuffed garnet. 50.-52. (canceled)
 53. The method of claim 1,wherein the source powder is characterized by the formulaLi_(7.1)Zr₂La₃O₁₂+0.5Al₂O₃, as batched.
 54. A slurry for preparing acast green film, the slurry comprising: at least two or more of: asolvent selected from the group consisting of methanol, ethanol,propanol, isopropanol, butanol, isobutanol, t-butanol, pentanol,hexanol, cyclohexanone cyclohexanol, methyl acetate, ethyl acetate,methyl-ethyl ketone (MEK), acetone, toluene, hexanes, acetic acid, andcombinations thereof; a binder selected from the group consisting offish oil, polyvinylbutylene (PVB), KD1, an acrylic acid, triton,phosphate esters, and combinations thereof; a plasticizer selected fromthe group consisting of a benzyl butyl phthalate and di-butyl phthalate;optionally a pH modifier; optionally a sintering aid selected from MgO,Al₂O₃, and combinations thereof; and a source powder selected from alithium-stuffed garnet.
 55. The slurry of claim 54, wherein the amountof source powder is at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or90% by weight.
 56. (canceled)
 57. The slurry of claim 54, wherein thesource powder is selected from the group consisting of lithium-stuffedgarnet, chemical precursors to lithium-stuffed garnet, and lithiumstuffed garnet with aluminum oxide dopants.
 58. (canceled)
 59. Theslurry of claim 54, wherein the source powder comprises garnet powdermilled to d₅₀ of about 3 μm, and wherein the binder comprises polymethyl methacrylate in MEK.
 60. (canceled)
 61. The slurry of claim 54,wherein the solvent is selected from methyl-ethyl ketone (MEK) ortoluene.
 62. The slurry of claim 54, wherein the solvent comprisesmethyl-ethyl ketone (MEK).
 63. The slurry of claim 54, wherein thesolvent further comprises isopropanol (IPA).
 64. The slurry of claim 54,wherein the solvent further comprises cyclohexanone. 65.-66. (canceled)67. The slurry of claim 54, wherein the solvent is an azeotrope.
 68. Theslurry of claim 54, wherein the source powder is a lithium-stuffedgarnet.
 69. The slurry of claim 68, wherein the amount oflithium-stuffed garnet in the slurry is at least 70% w/w.
 70. The slurryof claim 54, wherein a concentration of the source powder in the slurryis about 50 wt %, and wherein a concentration of the binder in theslurry is about 50 wt %.
 71. The slurry of claim 54, wherein aconcentration of the source powder in the slurry is about 2-80% w/w.72.-73. (canceled)
 74. The slurry of claim 54, wherein the green filmcontains flocs at a density of less than 100/mm² where a floc is abinder aggregate 5 μm in diameter as measured by FIB cross section SEMof a green film.
 75. A green tape, comprising: a source powder, whereinthe source powder is a lithium-stuffed garnet powder; a solvent; abinder; and a dispersant; wherein the green tape has a pycnometrydensity greater than 3.9 and less than 5.0 g·cm³.
 76. The green tape ofclaim 75, further comprising a member selected from a plasticizer, a pHmodifier, and a sintering aid. 77.-78. (canceled)
 79. The green tape ofclaim 75, comprising a pH modifier selected from citric acid or ammoniahydroxide.
 80. The green tape of claim 75, comprising a sintering aidselected from MgO, Al₂O₃, and combinations thereof.
 81. The green tapeof claim 75, wherein the solvent is an azeotrope.
 82. (canceled)
 83. Thegreen tape of claim 75, wherein the solvent is selected from methylethyl ketone (MEK), tetrahydrofuran, toluene, acetone, 1-butanol,2-butanol, cyclohexane, cyclohexanol, ethanol, isopropanol, methanol,1-propanol, propylene carbonate, hexane, 1-propanol, m-xylene, andpentane.
 84. (canceled)
 85. The green tape of claim 75, wherein thesolvent comprises methyl-ethyl ketone (MEK).
 86. The green tape of claim75, wherein the solvent further comprises isopropanol (IPA).
 87. Thegreen tape of claim 75, wherein the solvent further comprisescyclohexanone.
 88. The green tape of claim 75, wherein the ratio ofMEK:IPA is 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, or 2:8 w/w.
 89. The green tapeof 88 claim 75, wherein the amount of cyclohexanol is about 10-25% byweight.
 90. (canceled)
 91. The green tape of claim 75, comprising asource powder of a lithium-stuffed garnet having a density of 4 g/cm³,and a solvent comprising MEK and IPA.
 92. The green tape of claim 75,comprising a source powder of a lithium-stuffed garnet having a densityof 4 g/cm³, and a solvent comprising MEK, IPA, and cyclohexanone.
 93. Amethod of making a green tape, comprising: (a) providing a slurry,wherein the slurry comprises a lithium-stuffed garnet powder; (b)providing a binder mixture; (c) mixing the slurry with the bindermixture to form a mixed slurry; and (d) casting the mixed slurry toprovide a green tape.
 94. The method of claim 93, wherein the slurrycomprises at least two or more of: a solvent selected from the groupconsisting of methanol, ethanol, propanol, isopropanol, butanol,isobutanol, t-butanol, pentanol, hexanol, cyclohexanol, methyl acetate,ethyl acetate, methyl-ethyl ketone (MEK), acetone, toluene, hexanes,acetic acid, and combinations thereof; a binder selected from the groupconsisting of fish oil, polyvinylbutylene (PVB), KD1, an acrylic acid,triton, phosphate esters, and derivatives thereof; a plasticizerselected from the group consisting of a benzyl butyl phthalate anddi-butyl phthalate; optionally a pH modifier; optionally a sinteringaid; and a source powder selected from a lithium-stuffed garnet.95.-102. (canceled)
 103. The method of claim 93, wherein the green tapehas a solid loading greater than 50% w/w. 104.-107. (canceled)
 108. Themethod of claim 93, wherein the green tape is a thin film having a filmthickness less than 200 μm and greater than 1 nm. 109.-114. (canceled)115. The method of claim 93, further comprising (e) drying the greentape until it has an organic content amount of about 10-25% w/w, whereinthe organic content is the content other than the source powder. 116.The method of claim 93, further comprising (f) laminating a second greentape to the green tape made in claim 92 to make a stack of green tapes.117.-118. (canceled)